function Animal(name, age, color) {
    this.name = name
    this.age = age
    this.color = color

}

function Poultry(color, name, age, foot) {
    Animal.apply(this, [name, age, color])
    this.foot = foot
    this.show = function () {
        return "我是一只" + this.color + "" + this.name + ",我已经" + this.age + "岁了，我有" + this.foot + "条腿"
    }
}
let an = new Poultry("灰色的", "狗狗", 1, 4)
let an1 = new Poultry("白色的", "茶猫", 2, 4)
let an2 = new Poultry("黑色的", "母鸡", 1, 2)
app.innerHTML = an.show()
app1.innerHTML = an1.show()
app2.innerHTML = an2.show()